1 Samuel 29:1-3

Now the Philistines gathered together all their hosts to Aphek: and the Israelites encamped by the fountain which is in Jezreel. And the lords of the Philistines passed on by hundreds, and by thousands; and David and his men passed on in the rearward with Achish. Then said the princes of the Philistines, What do these Hebrews here? And Achish said unto the princes of the Philistines, Is not this David, the servant of Saul the king of Israel, who hath been with me these days, or rather these years, and I have found no fault in him since he fell away unto me unto this day?